Method of forming a valve bag



June 28, 1938. E. HOPPE 7 METHOD OF FORMING A VALVE BAG I Original Filed Sept. 21, 1934 3 Sheets-Sheet 1 F3. lb

4 Edgar Hoppe f June 28, E. HOPPE METHOD OF FORMING A VALVE BAG Original Filed Sept. 21, 1954 5 Sheets-Sheet 2 FTE--Ea lTEEb June 28 1938. E, HOPPE 2,122,062

METHOD OF FORMING A VALVE BAG Original Filed Sept. 21, 1954 5 Sheets-Sheet 3 BE. in.

21mm Edgar Hoppe Patented June 28, 1938 UNITED STATES METHOD OF FORMING A VALVE BAG Edgar Hoppe, Amsterdam, Netherlands, assignor to St. Regis Paper Company, New York, N. Y., acorporation of Delaware Original application September 21, 1934, Serial No. 744,959. Divided and this application December 2, 1936, Serial No. 113,871

1 Claim.

This invention relates to multiply valve bags of paper or similar material in which at least one end is closed to form a satchel bottom, and an object is to produce a new and improved 5 method of making bags. of this character by which a longer and more eff cient valve may be obtained without substantial waste of material.

According to one aspect of the invention, the lengthening of the valve is effected in such way that the outer parts of the tube forming the flaps are cut on one side of the bag tube at a different level from the other side or from the middle level of the steps in the case of a stepped end bag, and in such way that the flaps on the side where the valve is located are, longer than on the other side. This means that the corresponding cut is displaced with reference to the level of the other out and results in a corresponding shortening of the adjoining flap in the next succeeding bag length. This is not disadvantageous, since the valve is formed only on one side of the bag. v

The cut separating the valve flap from the longitudnal edges is made deeper than the level of the shortest step of the longitudinal flaps, and this enables lengthening of the valve flap at least to the height of the longest step in the case of a stepped end bag. The surface of contact between the longitudinal edge and the valve flap is thereby increased materially and the safety or reliability of the valve closure considerably enhanced.

The final result is that by these means, the valve flap is considerably lengthened, thereby allowing a more efficient valve formation in the caseof wholly or partly interpasted edges of the individual paper webs. The above described idea is not confined solely to stepped end bags, but is also applicable to bags the flaps of which are not stepped at the ends.

One embodiment of the invention is shown for purposes of illustration but not of limitation in the accompanying drawings in which Fig. 1a. is a plan view showing an unfolded closure forming part of the bag having stepped side flaps, the steps of which are unsymmetrical on opposite sides being separated from the folded end flaps by a longitudinal cut.

Fig. 1b is a view similar to Fig. 1a showing one side flap folded along the line g-h.

Fig. .20. is a plan view of a bag end similar to that shown in Fig. 1a, but having the flap elongated on the side forming a valve flap.

Fig. 2b is a plan view of a bag end similar to Fig. 20. except that the plies are not stepped.

Figs. 3a and 3b are plan views of a portion of a bag tube length showing the cutting lines for effecting the valve flap shown in Figs. 2a. and 2b.

Fig. 4 shows the shape of the ends of the unfolded individual tubes of a three wall bag with an elongate valve flap.

In the forms of the invention shown on the drawings, it is of no importance whether the bag is provided with gussets or not, orwhether it is an open mouth bag or a valve bag, with the exception of such improvements, which refer to the valve or its formation.

The Figures 1a and lb demonstrate the differ-- ent widths of the opposed sets of flaps I, 2, 3 of a three-wall bag tube, and the overlapping of longitudinal edges, after the side flaps 4 and 5, which latter are of equal width, have been folded inwardly.

In the upper part of Fig. 1a the visible steps of the longitudinal edges I, 2 and 3, and in the lower part of the figure, the invisible steps outlined with dashed lines and marked with figures in parentheses are shown; also steps (2) and (3) covered by the innermost longest step (I). After folding the lower side flap inwardly along the folding line (g-h), the several longitudinal edges of the plies are rendered visible, the innermost step (I) being disposed below and the steps (2) and (3) being disposed over the step (I). If the side flap shown in the upper part of the figure is folded inwardly along the line (z'k), it is clear that the wider step (I)- comes to lie over the steps I .and 2 of the opposite side and even partly covers the step (3). In order to show the separation lines the lines of the single steps are marked a.-b, c-d and ef, the lines resulting after folding the steps are marked (LL-b), (c-d) andv (e-f).

The Figures 2a and 2b are comprehensible without further explanation and show only the picture, which would result if from both side flaps 4 and 5 the flap intended for the formation of the valve (flap 5) is elongated. The measure of the additional lengthening 5a attained by means of the above described cutting of the valve flaps, is indicated by dashed lines. Of course, in case of a bag bottom of an entirely unstepped bag shown on Fig. 2b, only the upper layer of the unfolded closure, i. e. the inner layer of the side flaps is visible.

In the unseparated bag tube shown on Figs. 1 3a and 3b, the separating lines are indicated by the reference numerals 6, l and 8. '9 are cutting lines lying in the middle level, near the outer edge on the side not intended for valve formation, and. Ill are cutting lines shifted from the middle level on the side intended for valve formation, both lines extending longitudinally of the bag tube. It will be seen that the cutting lines ll extending longitudinally of the bag tube and separating the end flaps from the side fllaps extend up to the level of the shortest step.

Fig. 4 shows the cutting of the ends of the unfolded individual tubes of a three-wall bag, the steps of the side flaps being marked I, 2 and 3. The valve flap is indicated at 5, only one -layer being seen. On this flap are marked with dotted lines the planes l2, which come to lie against the side fiaps and are pastedto them when the valve flap is folded. The glued longitudinal seams l3, l4 and I5 lie as described above in the unstepped part of the bag, i. e. these seams terminate in the end flaps as distinguished from side flaps.

-This application constitutes a division of my co-pending application, Serial No. 744,959, filed September 21, 1934, and entitled Multiwall bag of paper or similar material and method'of its manufacture.

ing forming a bag tube, separating the bag tube into bag lengths by cutting across the tube, forming slits longitudinally of the tube adjacent the sides thereof, said cross cut running between said slits substantially midway of their length and from one of said slits to the adjacent side substantially midway the length of the slit and from the other slit to a point on the adjacent side out of line with the portion of the cross out between said slits, thereby forming an extension on one side of the tube, and closing the bag in the accustomed manner for forming a satchel bottom bag but leaving the flap formed from the extended side unpasted to the overlying flaps whereby it constitutes a valve.

EDGAR HOPPE. 

